In ink jet printing, ink is ejected from a narrow orifice in the direction of a substrate. In one type of ink jet printing, known as drop-on-demand printing, the ink is ejected in a series of drops. The drops may be produced and controlled using a piezoelectric ink jet head that has a large number of orifices (also referred to as nozzles). Each orifice is separately controllable to selectively eject ink at desired locations, or pixels, of the image. For example, an ink jet head may have 256 orifices that have spacing for a printing resolution of at least 100 pixels (dots) per inch (dpi) and sometimes far more than that. This dense array of orifices allows complex, highly accurate images to be produced. In high performance print heads, the nozzle openings typically have a diameter of 50 micrometers or less (e.g., around 25 micrometers), are separated at a pitch of 25-300 nozzles/inch, have a resolution of 100 to 3000 dpi or more, and provide drop sizes of about 2 to 50 nanograms (pl) or less. Drop ejection frequency is typically 10 kHz or more. A drop-on-demand piezoelectric print head is described in U.S. Pat. No. 4,825,227, the entire content of which is incorporated herein by reference.